1. Field
The present disclosure relates to a fuel cell.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell includes a membrane electrode assembly (MEA), in which an anode electrode is disposed on one side of a solid-polymer electrolyte membrane and a cathode electrode is disposed on the other side of the solid-polymer electrolyte membrane. The solid-polymer electrolyte membrane is made from a polymer ion-exchange membrane. The MEA and a pair of separators, sandwiching the MEA therebetween, constitute a power generation cell (unit cell). Several tens to several hundreds of such power generation cells are stacked and used, for example, as a vehicle fuel cell stack.
Typically, a fuel cell has a so-called internal manifold structure for supplying a fuel gas and an oxidant gas, each of which is a reactant gas, respectively to anode electrodes and cathode electrodes of power generation cells that are stacked.
The internal manifold structure includes a reactant gas inlet manifold (fuel gas inlet manifold, oxidant gas inlet manifold) and a reactant gas outlet manifold (fuel gas outlet manifold, oxidant gas outlet manifold), each extending through the power generation cells in a stacking direction in which the power generation cells are stacked. The reactant gas inlet manifold is connected to an inlet of a reactant gas channel (fuel gas channel, oxidant gas channel), which supplies a reactant gas along an electrode surface; and the reactant gas outlet manifold is connected to an outlet of the reactant gas channel.
In this case, the reactant gas channel is connected to each of the reactant gas inlet manifold and reactant gas outlet manifold through a connection channel, which has parallel grooves or the like through which the reactant gas can flow smoothly and uniformly. Regarding such a structure, Japanese Patent No. 4634933, for example, describes a fuel cell that is devised to achieve a desirable sealing ability with an economical and simple structure.
In this fuel cell, a separator has a connection channel that connects a reactant gas manifold and a reactant gas channel to each other. At least one of gas diffusion layers of a membrane electrode assembly has a superposed portion that seals the connection channel by being superposed on the connection channel and pressed against the separator.